If you are in a spaceship with no windows and are coasting along at 100mph or 1000mph or 298,000,000m/s (not accelerating or braking), you are in an inertial frame of reference.
There is no test you can do to tell if the spaceship is actually moving or not. Physic is fascinating.
https://video.nostr.build/056f2427f8571ff6ccb282dd0143fed1537edd023801f6d31788406f4b31161e.mp4
that one i get.
but what i never got was how a photon send to one direction and another photon send the opposite direction both with light speed but the relative speed measured from one photon to with the other photon gives you also only light speed.
Yeah, that's where we depart from classical physics. The constancy of the speed of light is a fundamental part of relativity.
Without windows, can’t you still have sensors and antennae to measure the Doppler shift of celestial objects?
I know, I’m such a buzz kill.
True, but it's still not objective. You would be moving 100mph according to some objects, 1000000mph according to other objects.
You realize that all velocities are relative, right?
That's literally what I just told you.
Oddbean new post about login | logout